THERE is a Sioux war. Several times in the week we read in the morning paper that there has been a gallant attack by our forces, who were disposed with great skill, routing the savages, whose loss is believed to be very great, but who, as usual, carried off their dead. What is this Sioux war? Who is responsible for it? Who has broken faith? Who has lied and swindled? Is it the red savage or the civilized white man? Is it heroic to deceive an ignorant Indian, and sentimental to insist that a great civilized nation shall keep its word? These are questions which are suggested by the slightest inquiry into the causes of the Indian war, and the answers to many of them are not agreeable to the pride or conscience of honorable Americans. Those answers may be found in a document which has escaped general attention during the Presidential excitement, but which is one of the most important of the year. It is the report of the Sioux Commission which was appointed last August. The report was made to the Hon. J.Q.SMITH, Commissioner of Indian Affairs, in December last, and is well worthy universal attention and consideration. The Commission consisted of nine gentlemen selected for their acquaintance with the Indians and their friendship for them. The chairman was Colonel GEORGE W. MONEYPENNY, of Ohio, who was Indian Commissioner more than twenty years ago; and among the members were a grandson of DANIEL BOONE, who has been familiar with the Indians for fifty-five years, and Bishop WHIPPLE, of Minnesota, the brave and persistent friend of the Indians, whose interest in them and sympathy for them recall those of JOHN ELIOT in the early days of New England. The report of the Commission is long, but there is seldom a public document so full of earnest felling, while its statements of fact are entirely new, except to the very few who care to keep themselves acquainted with the details of the national guilt toward the Indians. The testimony of military men and of all who have had the most intimate dealings with those people shows that the troubles do not begin with them, but with the national bad faith. The Sioux, says the report, were one of the finest bodies of Indians upon the continent. NICOLLET, who visited all the Indian tribes, considered them superior to all. The officers of the Northwest Fur Company testify to their uniform friendship for the whites; and it was the boast of the Sioux that for thirty-five years their hands had not been stained with the blood of the white man. They occupied a vast territory between the Mississippi and the Rocky Mountains, and from the British possessions to the Kansas line. In 1825 the Sioux acknowledged that they were within the limits of the United States, and recognized the supremacy of the government, and the government pledged them its protection and kind care. In 1851 the California emigration made a new treaty necessary. This confirmed peaceful relations, conceded the right of the government to make military roads, and the Sioux agreed to make restitution for any injury done by them to any citizen of the United States. The government agreed by treaty to pay the Sioux fifty thousand dollars for fifty years. The Senate amended the treaty by limiting the appropriation to ten years. The amendment was never submitted to the Indians. They believed the treaty to be in force, and went to war, as we should have done, to maintain their rights. Then came the mixed Commission, with General SHERMAN at the head. Generals HARNEY, TERRY, and AUGUR were also members. They reported unanimously that we alone were responsible for the War. Naturally the Indians were willing to make another treaty, except with a pledge on our part that no white man should ever enter their territory. The Commission sympathized with them. Its report is eloquent with honorable feeling. “It is said that our wars with them have been almost constant. Have we been uniformly unjust? We answer unhesitatingly, Yes.” These are the words of tried and brave soldiers. The Commission made a treaty and gave the pledge. The treaty was ratified by the Senate. It was signed by the President. The national faith was pledged. The Constitution makes treaties the law of the land. The ordinance of 1787 guarantees that the territory of the Indians shall never be invaded, “unless in just and lawful wars authorized by Congress.” There is a Sioux war to-day. By what authority is that war waged? The treaty conceded to the Indians the right to hunt in the unceded territory north and west of the Sioux reservation. General SHERIDAN issued an order in 1869 that all Indians found outside of the reservation would be considered hostile. The Black Hills expedition of the brave General CUSTER was in direct violation of the treaty. The Commission emphasize one significant fact, the observation of which, when he was a young officer upon the frontier, led General GRANT to his wise Indian policy. It is that the English government in Canada has spent no money in Indian wars since the American Revolution, has lost no lives by massacre, has had no desolated settlements, and its Indians have been always loyal. The reason is very simple. The government has kept faith. It has given the Indians the protection of the law, has fostered missions, and has placed over them agents who hold office during good behavior. In a word, as General GRANT has said, it has treated the Indians as if they had rights which white men are bound to respect. It has not regarded them as vermin to be exterminated, and it has not contemptuously broken its own pledged faith. Our system of treaties with the Indian tribes is foolish, but understandings and arrangements with them are indispensable, and require sagacious, experienced, honest, and well-paid agents. The Commission recommend an independent department of Indian affairs, and assert that if by the independence of such a department the fearful cost of one Indian war could be saved, it would be the wisest economy. The Commission have made an arrangement with Sioux chiefs at the agencies, which they trust will be faithfully carried out by the government; but they look to Congress for general redress of Indian grievances, persuaded that without instant and appropriate legislation for the protection and government of the Indians, they must perish.